This is a phase II/III, open, multicentre study in which patients with acromegaly will receive IPSTYL over a period of up to sixteen weeks. Patients who are well controlled and have GH < 2.5 ng/ml following two injections of IPSTYL given at 14-day intervals, will receive in total 6 injections of IPSTYL every 14 days, for a minimum of 12 weeks. Patients who fail to respond sufficiently after the first two injections of IPSTYL when given at a 14 day interval, will receive three injections at 10-day intervals. These patients will, after having received their fifth injection, be re-evaluated. Patients who are controlled and exhibit GH < 2.5 ng/ml and IGF-1 values normalized, or have GH >2.5 ng/ml or elevated IGF-1 values but have symptomatic improvement, will continue in the study and receive a further six IPSTYL injections at 10-day intervals, for a total of 11 injections.